Diet strongly influences the gut microbiota of surgeonfishes

Keywords

16S rRNA genes, 454 pyrotags, Epulopiscium, Gut microbiota, Surgeonsh

Abstract

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​Intestinal tracts are among the most densely populated microbial
ecosystems. Gut microbiota and their influence on the host have been
well characterized in terrestrial vertebrates but much less so in fish.
This is especially true for coral reef fishes, which are among the most
abundant groups of vertebrates on earth. Surgeonfishes (family:
Acanthuridae) are part of a large and diverse family of reef fish that
display a wide range of feeding behaviours, which in turn has a strong
impact on the reef ecology. Here, we studied the composition of the gut
microbiota of nine surgeonfish and three nonsurgeonfish species from the
Red Sea. High-throughput pyrosequencing results showed that members of
the phylum Firmicutes, especially of the genus Epulopiscium,
were dominant in the gut microbiota of seven surgeonfishes. Even so,
there were large inter- and intraspecies differences in the diversity of
surgeonfish microbiota. Replicates of the same host species shared only
a small number of operational taxonomic units (OTUs), although these
accounted for most of the sequences. There was a statistically
significant correlation between the phylogeny of the host and their gut
microbiota, but the two were not completely congruent. Notably, the gut
microbiota of three nonsurgeonfish species clustered with some
surgeonfish species. The microbiota of the macro- and microalgavores was
distinct, while the microbiota of the others (carnivores, omnivores and
detritivores) seemed to be transient and dynamic. Despite some
anomalies, both host phylogeny and diet were important drivers for the
intestinal microbial community structure of surgeonfishes from the Red
Sea.